Outdoor display apparatus

ABSTRACT

An outdoor display apparatus includes a housing having an opening, an inlet port and an outlet port, a transparent member disposed in tile opening, a liquid crystal display panel module disposed in the housing so that the liquid crystal display panel module is spaced from the transparent member to define a gap therebetween, the liquid crystal display panel module being provided at a front thereof with a liquid crystal display panel, a circuit disposed at a rear of the liquid crystal display panel module, an optical film disposed inside the transparent member at a position corresponding to the liquid crystal display panel, and an air circulation device to distribute air introduced through the inlet port so that the distributed air passes through the gap between the transparent member and the liquid crystal display panel and through the circuit and is discharged through the outlet port.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/361,020, filed on Jan. 30, 2012, which is currently pending, andclaims priority under 35 U.S.C, § 119 from Korean Patent Application No.10-2011-0010313 filed with the Korean Intellectual Property Office onFeb. 1, 2011, the disclosures of each of which are incorporated hereinby reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present general inventive concept relate to anoutdoor display apparatus.

2. Description of the Related Art

An outdoor display apparatus is an apparatus disposed outside a buildingto display an image. An example of an outdoor display apparatus includesa signboard.

Generally, an outdoor display apparatus includes a housing, atransparent member disposed at one side of the housing, and a displaypanel disposed inside the transparent member to display an image.Recently, an outdoor display apparatus using a liquid crystal displaypanel as a display panel has been used.

SUMMARY OF THE INVENTION

The present general inventive concept provides an outdoor displayapparatus that improves visibility of an image displayed on a liquidcrystal display panel and prevents the liquid crystal display panel fromdeteriorating.

Additional aspects and advantages of the present general inventiveconcept will be set forth in part in the description which follows and,in part, will be obvious from the description, or may be learned bypractice of the general inventive concept

The foregoing and/or other features and utilities of the present generalinventive concept may be achieved by providing an outdoor displayapparatus including a housing having an opening formed at a frontthereof, an inlet port through which air is introduced inside thehousing, and an outlet port through which air is discharged outside thehousing, a transparent member disposed in the opening, a liquid crystaldisplay panel module disposed in the housing so that the liquid crystaldisplay panel module is spaced from the transparent member to define agap therebetween, the liquid crystal display panel module being providedat the front thereof with a liquid crystal display panel to display animage, a circuit disposed at the rear of the liquid crystal displaypanel module, an optical film disposed inside the transparent member ata position corresponding to the liquid crystal display panel of theliquid crystal display panel module, and an air circulation device todistribute air introduced through the inlet port so that the distributedair passes through the gap between the transparent member and the liquidcrystal display panel and through the circuit and is discharged throughthe outlet port.

The optical film may include a polarizing film having the same opticalaxis as light passing through the liquid crystal display panel.

The polarizing film may have a surface area equal to or greater thanthat of an effective display area of the liquid crystal display paneland equal to or less than that of the transparent member.

The optical film may further include a ¼ wavelength plate attached tothe polarizing film to convert an optical axis of an image displayed onthe liquid crystal display panel into circular polarized light.

The polarizing film and the ¼ wavelength plate may have a surface areaequal to or greater than that of an effective display area of the liquidcrystal display panel and equal to or less than that of the transparentmember.

The outdoor display apparatus may further include an anti-static filmdisposed at the transparent member and/or the liquid crystal displaypanel to restrain generation of static electricity.

The outdoor display apparatus may further include an anti-reflectionfilm disposed at the transparent member and/or the liquid crystaldisplay panel to reduce reflection of light.

The air circulation device may be disposed at the lower part of thehousing, the inlet port may be provided at the lower part of thehousing, and the outlet port may be provided at the upper part of thehousing.

The air introduced through the inlet port may be distributed so thatsome of the air passes through the gap between the transparent memberand the liquid crystal display panel and is discharged through theoutlet port and so that the remainder of the air passes through thecircuit and is discharged through the outlet port.

The liquid crystal display panel module may further include a backlightunit disposed to irradiate light to the liquid crystal display panel,and the circuit may include a drive unit to drive the liquid crystaldisplay panel and the backlight unit, a signal processing unit toreceive and display an external signal on the liquid crystal displaypanel, and a power supply unit to convert and distribute external powerto the drive unit and the signal processing unit.

The air circulation device may include a blowing fan, a drive motor torotate the blowing fan, and a guide duct, in which the blowing fan isdisposed, having a first discharge port to guide air discharged from theblowing fan to the gap between the transparent member and the liquidcrystal display panel.

The guide duct may be further provided with a second discharge port toguide some of the air discharged from blowing fan to the circuit.

The first discharge port may guide 70% of the air discharged fromblowing fan and the second discharge port may guide 30% of the airdischarged from blowing fan.

The outdoor display apparatus may further include a first filterdisposed inside the inlet port to remove dust from air introducedthrough the inlet port and a second filter disposed inside the outletport to remove dust from air discharged through the outlet port.

The foregoing and/or other features and utilities of the present generalinventive concept may be achieved by providing an outdoor displayapparatus including a housing having an opening formed at a frontportion of the housing, a transparent member disposed in the opening ofthe housing, a display panel module disposed in the housing, having adisplay panel spaced-apart from the transparent member to define a firstgap and to display an image thereon and having a circuit spaced-apartfrom a rear portion of the housing to define a second gap and to controlthe image of the display panel, and an air circulation device todistribute a selectively temperature-controlled air into the first gapand the second gap.

The outdoor display apparatus may further include an optical filmdisposed on a viewing path of the image from the display panel to anoutside of the housing through the transparent member to affect lightpassing between the transparent member and the display panel.

The outdoor display apparatus may further include an optical filmdisposed on a viewing path of the image from the display panel to anoutside of the housing through the transparent member to reduce at leastone of transmission and reflection of light between the transparentmember and the display panel.

The transparent member may have a first effective area, the optical filmmay have a second effective area, and the display panel may have a thirdeffective area different from at least one of the first effective areaand the second effective area.

The air circulation device may include an air controlling unit tocontrol a characteristic of air to generate theselectively-temperature-controlled air.

The air circulation device may include a heater to heat air to generatethe selectively temperature-controlled air according to at least one ofa temperature and humidity.

The circuit of the display panel module may be a first heat generatingsource to be cooled by non-temperature-controlled air of the aircirculation device, and the air circulation device may include a secondheat generating source to generate the temperature-controlled air tocontrol characteristics of the transparent member, the display panel andthe first gap.

The housing may include an inlet port to introduce air into the aircirculation device disposed an inside of the housing, and an outlet portto discharge the air passing through the first gap and the second gap.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present generalinventive concept will become apparent and more readily appreciated fromthe following description of the embodiments, taken in conjunction withthe accompanying drawings of which:

FIG. 1 is a perspective view illustrating an outdoor display apparatusaccording to an embodiment of the present general inventive concept;

FIG. 2 is a sectional view illustrating an outdoor display apparatusaccording to an embodiment of the present general inventive concept; and

FIG. 3 is an enlarged view of a portion A of FIG. 2 to illustrate anexample of a transparent member of an outdoor display apparatusaccording to an embodiment of the present general inventive concept.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentgeneral inventive concept, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to the likeelements throughout. The embodiments are described below in order toexplain the present general inventive concept while referring to thefigures.

As illustrated in FIGS. 1 and 2, an outdoor display apparatus accordingto an embodiment of the present general inventive concept includes ahousing 10 forming an external appearance of the outdoor displayapparatus, the housing 10 having an opening 10 a formed at a frontportion thereof, a transparent member 20 formed of a transparentmaterial and disposed in the opening 10 a, and a display unit, forexample, a liquid crystal display panel module 30 disposed in thehousing 10 to generate an image. The display unit may be another type ofa display panel module to generate or display an image on a screen of adisplay panel. Although the outdoor display apparatus is illustrated asan embodiment of the present general inventive concept, the outdoordisplay apparatus may be a display apparatus disposed in an outsideenvironmental area, that is, a non-air controlled area, a lowtemperature area, a high humid area, and so on.

The housing 10 is formed in a shape of a hexahedral box or a box-likeshape. The opening 10 a is provided at an upper part of the frontportion of the housing 10.

The transparent member 20 is formed of a transparent material to have ahigh strength, like reinforced glass. The transparent member 20 may bedisposed at the upper part of the front portion of the housing 10 sothat the transparent member 20 corresponds to the liquid crystal displaypanel module 30 disposed in the housing 10. An image is generated byand/or displayed on the liquid crystal display panel module 30 and thenis viewed from an outside of the housing 10 through the transparentmember 20. The housing may have a coupling element 10 a to connect thetransparent member 20 to the housing 10. The coupling element may beformed at an area to define the opening of the housing 10.

The liquid crystal display panel module 30 may be disposed at an upperpart of the housing 10 therewithin. The liquid crystal display panelmodule 30 may include a liquid crystal display panel 31 to display animage and a backlight unit 32 disposed at a rear portion of the liquidcrystal display panel 31 to irradiate light to the liquid crystaldisplay panel 31. A circuit 33 is disposed at the rear portion of theliquid crystal display panel module 30 to control operations of theliquid crystal display panel 31 and the backlight unit 32. The liquidcrystal display panel 31 of the liquid crystal display panel module 30is spaced-apart from the transparent member 20 by a distance to define agap, through which air flows.

A screen of the liquid crystal display panel 31 of the liquid crystaldisplay panel module 30 may be disposed parallel to a major surface ofthe transparent member 20. In this case, the distance between thetransparent member 20 and the liquid crystal display panel 31 of theliquid crystal display panel module 30 may be constant. However, it ispossible that the transparent member 20 can form an angle with a screenof the liquid crystal display panel 31 of the liquid crystal displaypanel module 30. In this case, the distance between the transparentmember 20 and the liquid crystal display panel 31 of the liquid crystaldisplay panel module 30 may not be constant but may be variableaccording to a distance from a bottom the housing 10 or according to adistance from a side of the housing 10.

A direct type backlight unit, having a light source disposed at the rearof the liquid crystal display panel 31, to directly irradiate light tothe liquid crystal display panel 31 or an edge type backlight unit,having a light source disposed at the edge of the liquid crystal displaypanel 31, to disperse light through a light guide plate and indirectlyirradiate light to the liquid crystal display panel 31 may be used asthe backlight unit 32. In this embodiment, a direct type backlight unitis used as the backlight unit 32.

The circuit 33 includes a drive unit 33 a to drive the liquid crystaldisplay panel 31 and the backlight unit 32, a signal processing unit 33b to receive an external signal and display an image according to theexternal signal on the liquid crystal display panel 31, and a powersupply unit 33 c connected to an external power source to convert powerreceived from the external power source and distribute the convertedpower to the drive unit 33 a and the signal processing unit 33 b.

It is also possible that the signal processing unit 33 b may have animage reproducing unit (not illustrated) to generate a signal tocorrespond to an image to be displayed on the liquid crystal displaypanel 31. It is also possible that the signal processing unit 33 b mayhave a terminal (not illustrated) to be connected to an external deviceto receive a signal to correspond to the image to be displayed on theliquid crystal display panel 31. The signal processing unit 33 b mayhave a controller to process the signal to drive the drive unit and alsocontrol the power supply unit 33 c according to a state of the signalcorresponding to the image.

Since the outdoor display apparatus is installed in an outdoor space,the liquid crystal display panel 31 is heated by sunlight reaching theliquid crystal display panel 31 through the transparent panel 20. Inthis case, the liquid crystal display panel 31 may deteriorate or aperformance thereof is lowered. The sunlight or other light may bedirectly or indirectly reached to the liquid crystal display panel 31through the transparent panel 20 to affect the performance of the liquidcrystal display panel module 30.

In this embodiment, the outdoor display apparatus may include an aircirculation device 40 to circulate external air in the housing 10 tomaintain an internal temperature of the housing 10 within apredetermined temperature range. To this end, the housing 10 is providedat a lower part of the rear thereof with an inlet port 10 b, throughwhich air is introduced into the housing 10 and at an upper part of therear portion thereof with an outlet port 10 c, through which air havingbeing circulated in the housing 10 is discharged from the housing 10.

Inside the inlet port 10 b is disposed a first filter 11 to filter aforeign material contained in air introduced through the inlet port 10b. Inside the outlet port 10 c is disposed a second filter 12 to filterout foreign material contained in air discharged through the outlet port10 c.

Between the air circulation device 40 and the first filter 11 isdisposed a heater 13 to heat air introduced through the inlet port 10 b,thereby preventing the liquid crystal display panel 31 from being frozenat a low temperature, for example, a temperature in winter. The heater13 may be selectively, manually, and/or automatically activated to raisethe temperature of the inside of the housing 10 according to anenvironmental condition of a sensor (not illustrated), a manipulation ofa switch (not illustrated) formed on the housing, and/or a command tooperate the heater 13, respectively.

The air circulation device 40 includes a blowing fan 41 to disposed atthe lower part of the housing 10 inside the housing 10 to generate asuction force and a blowing force through a rotation thereof, a drivemotor 42 to generate a rotational force to rotate the blowing fan 41,and a guide duct 43, in which the blowing fan 41 is disposed, to guideair suctioned into the blowing fan 41 and air discharged from theblowing fan 41. Accordingly, external air is introduced into the housing10 through the inlet port 10 b, is circulated in the housing 10, and isdischarged from the housing 10 through the outlet port 10 c.

In this embodiment, the blowing fan 41 may be a centrifugal fan, forexample, to receive air in an axial direction and discharge the receivedair in a radial direction.

The guide duct 43 includes a suction port 43 a provided in the axialdirection of the blowing fan 41 so that air introduced through the inletport 10 b of the housing 10 is suctioned into the blowing fan 41 throughthe suction port 43 a, and discharge ports 43 b and 43 c disposedoutside the blowing fan 41 in the radial direction of the blowing fan 41so that air discharged from the blowing fan 41 is supplied to the liquidcrystal display panel module 30 through the discharge ports 43 b and 43c.

In this embodiment, the air circulation device 40 cools the liquidcrystal display panel 31 heated by sunlight and removes heat generatedfrom the circuit 33.

The air circulation device 40 may distribute the air discharged from theblowing fan 41 such that a first portion of the air is supplied to thegap between the liquid crystal display panel 31 and the transparentmember 20 and a second portion of the air is supplied to a second gapwhere the circuit 33 is disposed so as to simultaneously cool the liquidcrystal display panel 31 and the circuit 33. The air circulate device 40may include a divider structure (not illustrated) to define or form thedischarge ports 43 b and 43 c to direct the air supplied from theblowing fan 41 to one or both of the gap and the second gap.

To this end, the discharge ports 43 b and 43 c include a first dischargeport 43 b to discharge the first portion of the air discharged from theblowing fan 41 to the gap between the transparent member 20 and theliquid crystal display panel 31 and a second discharge port 43 c todischarge the second portion of the air discharged from the blowing fan41 to the circuit 33. Accordingly, the first portion of the airdischarged from the blowing fan 41 passes through the gap between thetransparent member 20 and the liquid crystal display panel 31 throughthe first discharge port 43 b to cool the liquid crystal display panel31 and is discharged through the outlet port 10 c, thereby preventingdeterioration of the liquid crystal display panel 31, and the secondportion of the air discharged from the blowing fan 41 is supplied to thesecond gap corresponding to the circuit 33 through the second dischargeport 43 c to cool the circuit 33 and is discharged through the outletport 10 c, thereby preventing overheating of the circuit 33. That is,the liquid crystal display panel 31 and the circuit 33 may besimultaneously cooled by the air circulation device 40.

In the outdoor display apparatus, deterioration of the liquid crystaldisplay panel 31 via interaction with sunlight is prevented. In thisembodiment, the first portion may be, for example, 70% of the airdischarged from the blowing fan 41 to be supplied to the gap between thetransparent member 20 and the liquid crystal display panel 31 throughthe first discharge port 43 b, and the second portion may be, forexample, 30% of the air discharged from the blowing fan 41 to besupplied to the second gap corresponding to the rear portion of theliquid crystal display panel 31, i.e., the backlight unit 32 and thecircuit 33, through the second discharge port 43 c.

In this embodiment, the first discharge port 43 b and the seconddischarge port 43 c are designed so that 70% of the air discharged fromthe blowing fan 41 is supplied to the gap between the transparent member20 and the liquid crystal display panel 31 through the first dischargeport 43 b and 30% of the air discharged from the blowing fan 41 issupplied to the circuit 33 through the second discharge port 43 c. Whensufficient air is not supplied to the gap between the transparent member20 and the liquid crystal display panel 31 due to flow resistance, anauxiliary blowing fan (not illustrated) may be disposed in the firstdischarge port 43 b.

The outdoor display apparatus may have a sensor (not illustrated) todetect at least one of an inside temperature and an outside temperatureand a controller (not illustrated) to control the heater 13 and/or theair circulation device 40. The sensor (not illustrated) may be disposedon the housing 10 or an inside of the housing 10. The controller (notillustrated) may be disposed in the air circulation device 40 or may beembodied in the circuit 33 of the liquid crystal display panel module 30such that the circuit 33 of the liquid crystal display panel 31 cancontrol the liquid crystal display panel 31 and the air circulationdevice 40. The controller (not illustrated) may control the heater 13according to the detected temperature. It is possible that thecontroller may control the heater 13 according to a command included inthe signal received at the circuit 33 from an external device.

The outdoor display apparatus may perform a heating mode to operate theheater 13 and an air circulating mode to operate the motor 42 and theblowing fan 41. The air circulating mode may not include the heatingmode.

It is possible that the outdoor display apparatus may include a sensor(not illustrated) to detect a humidity at an inside of the housing 10and/or an outside of the housing 10 such that the heating mode and/orthe air circulating mode can be performed according to the detectedhumidity and/or the detected temperature. When humidity is high, vaporcondensation may be formed on the transparent member 20 or the liquidcrystal display panel module 30. In this case, the water or vaporcondensation may be removed from the transparent member 20 and/or theliquid crystal display panel module 30 or from the gap and/or the secondgap by selectively performing the heating mode and/or the aircirculating mode.

When sunlight is reached the liquid crystal display panel 31 through thetransparent member 20, is reflected by the liquid crystal display panel31, and/or is transmitted back to the outside thereof, contrast of animage displayed on the liquid crystal display panel 31 may be lowered.

In this embodiment, as illustrated in FIG. 3, an optical film isdisposed between the transparent 20 and the liquid crystal display panel31 to prevent contrast of the image displayed on the liquid crystaldisplay panel 31 from being lowered. The optical film may include apolarizing film 21 having the same optical axis as the image displayedon the liquid crystal display panel 31 and a ¼ wavelength plate 22 toconvert the optical axis of the image displayed on the liquid crystaldisplay panel 31 into circular polarized light. It is possible that theoptical film may change a first characteristic of the light into asecond characteristic.

The polarizing film 21 and the ¼ wavelength plate 22 are sequentiallydisposed in an advancing direction of the light. In this embodiment, thepolarizing film 21 and the ¼ wavelength plate 22 are sequentiallydisposed on or inside the transparent member 20. That is, the polarizingfilm 21 is disposed inside the transparent member 20, and the ¼wavelength plate 22 is disposed inside the polarizing film 21. Also, thepolarizing film 21 and the ¼ wavelength plate 22 have a surface areaequal to or greater than that of an effective display area of the liquidcrystal display panel 31 and equal to or less than that of thetransparent member 20 to efficiently block transmission and/orreflection of light in the effective display area of the liquid crystaldisplay panel 31.

The polarizing film 21 transmits only a specific optical axis componentof the polarized light and absorbs the remainder of the polarized light.The ¼ wavelength plate 22 may have an optical axis with an inclinationof 45 degrees to the optical axis of the polarizing film 21.

The polarizing film 21 and the ¼ wavelength plate 22 are operated asfollows. In the following description, it is assumed that the opticalaxis of the polarizing film 21 is a Y axis, and the optical axisperpendicular to the optical axis of the polarizing film 21 is an X axisfor convenience of description.

When sunlight is incident upon the transparent member 20 of the outdoordisplay apparatus, a portion of the sunlight is reflected by thetransparent member 20, and the remaining portion of the sunlight istransmitted through the transparent member 20 and is incident upon thepolarizing film 21. The polarizing film 21 transmits only Y-axispolarized light corresponding to the optical axis of the polarizing film21, i.e., the Y axis, and absorbs the remainder of the polarized light.The polarized light, having passed through the polarizing film 21, isincident upon a front portion of the ¼ wavelength plate 22 and isconverted into circular polarized light while passing through the ¼wavelength plate 22.

The circular polarized light, having passed through the ¼ wavelengthplate 22, is reflected by the liquid crystal display panel 31 and isincident upon the rear of the ¼ wavelength plate 22. While passingthrough the ¼ wavelength plate 22, the reflected light is converted intoX-axis polarized light perpendicular to the optical axis of thepolarizing film 21, i.e., the Y axis. The X-axis polarized light isincident upon the polarizing film 21. Since the optical axis of thepolarizing film 21 is the Y axis, the X-axis polarized light is nottransmitted. The X-axis polarized light may be absorbed by thepolarizing film 21. Although sunlight passes through the transparentmember 20 and reaches the liquid crystal display panel 31, lightreflected by the liquid crystal display panel 31 is absorbed by thepolarizing film 21, thereby preventing the light from being transmittedto the outside thereof.

Consequently, contrast of an image displayed on the liquid crystaldisplay panel 31 is prevented from being lowered by sunlight, therebyimproving visibility of an image displayed on the liquid crystal displaypanel 31.

Although FIG. 3 illustrates only the polarizing film 21 and the ¼wavelength plate 22 are provided, the present general inventive conceptis not limited thereto. In addition to the polarizing film 21 and the ¼wavelength plate 22, a functional film may be attached to the frontand/or rear portions of the transparent member 20 or the front portionof the liquid crystal display panel 31 to improve visibility of an imagedisplayed on the liquid crystal display panel 31. The functional filmmay include an anti-static film to restrain generation of staticelectricity, preventing dust from sticking to the front of thetransparent member 20 or the liquid crystal display panel 31 and ananti-reflection film disposed at the transparent member 20 or the liquidcrystal display panel 31 to reduce reflection of light.

In this embodiment, the polarizing film 21 and the ¼ wavelength plate 22are disposed inside the transparent member 20, to which, however,embodiments of the present general inventive concept are not limited.When the polarizing film 21 and the ¼ wavelength plate 22 may bedisposed at the front portion of the liquid crystal display panel 31 orwhen the polarizing film 21 and the ¼ wavelength plate 22 may bedisposed in the gap between transparent member 20 and the liquid crystaldisplay panel 31, the polarizing film 21 and the ¼ wavelength plate 22may be spaced apart from the transparent member 20 and the liquidcrystal display panel 31 to improve the visibility and other factors ofthe image.

The transparent member 20 may have a first area, the optical film mayhave a second area, and the liquid crystal display panel 31 may have athird area to display an image. The image displayed in the third area ofthe liquid crystal display panel 31 may be transmitted to an outside ofthe housing 10 through the second area of the optical film and the firstarea of the transparent member 20. Although the liquid crystal displaypanel 31 is spaced apart from the transparent member 20, the image ofthe liquid crystal display panel 31 can be displayed to a viewer at apredetermined viewing angle since the first area is larger than thethird area.

The sunlight may be transmitted through the first area of thetransparent member 20, the second area of the optical film, and thethird area of the liquid crystal display panel 31. Since the liquidcrystal display panel 31 is spaced apart from the transparent member 20,all of the sunlight incident on the first area of the transparent member20 may not be transmitted to the optical film and/or the liquid crystaldisplay panel 31 depending on an incident angle.

As is apparent from the above description, air flows via the gap betweenthe liquid crystal display panel and the transparent member and to thecircuit to prevent the liquid crystal display panel from deterioratingby sunlight and to prevent the circuit from being overheated by sunlightor by an operation thereof, and the optical film is disposed between thetransparent member and the liquid crystal display panel to preventcontrast of an image displayed on the liquid crystal display panel frombeing lowered by sunlight, thereby improving visibility of the imagedisplayed on the liquid crystal display panel.

Although a few embodiments of the present general inventive concept havebeen shown and described, it will be appreciated by those skilled in theart that changes may be made in these embodiments without departing fromthe principles and spirit of the general inventive concept, the scope ofwhich is defined in the appended claims and their equivalents.

What is claimed is:
 1. An outdoor display apparatus comprising: ahousing having an opening formed at a front portion thereof, an inletport through which air is introduced, and an outlet port through whichair is discharged; a transparent member disposed in the opening; aliquid crystal display panel module disposed in the housing, spacedapart from the transparent member to define a gap therebetween, andprovided with a liquid crystal display panel at a front side thereof todisplay an image; a circuit disposed at a rear portion of the liquidcrystal display panel module; a filter coupleable to an inside of theinlet port to remove dust from air introduced through the inlet port; atemperature controlling unit configured to control a temperature insidethe housing and disposed between the filter and the gap, and an opticalfilm disposed inside the transparent member, the optical film extendsparallel to the liquid crystal display panel of the liquid crystaldisplay panel module, the optical film being disposed on an innersurface of the transparent member, and the optical film including: apolarizing film having an optical axis the same as an optical axis oflight passing through the liquid crystal display panel, and a ¼wavelength plate to convert an optical axis of the image displayed onthe liquid crystal display panel into circular polarized light having anoptical axis perpendicular to the optical axis of the polarizing filmthat is the same as the optical axis of the liquid crystal displaypanel, wherein the liquid crystal display panel is configured to reflectthe circular polarized light that has passed through the ¼ wavelengthplate of the optical film, and the ¼ wavelength plate is a single ¼wavelength plate of the outdoor display apparatus which converts theoptical axis of the image in the outdoor display apparatus.
 2. Theoutdoor display apparatus of claim 1, wherein the polarizing film has asurface area greater than that of an effective display area of theliquid crystal display panel and equal to that of the transparentmember.
 3. The outdoor display apparatus of claim 1, wherein thepolarizing film and the ¼ wavelength plate have a surface area greaterthan that of an effective display area of the liquid crystal displaypanel and equal to that of the transparent member.
 4. The outdoordisplay apparatus according to claim 1, wherein the liquid crystaldisplay panel module further comprises a backlight unit disposed toirradiate light to the liquid crystal display panel, and the circuitcomprises a drive unit to drive the liquid crystal display panel and thebacklight unit, a signal processing unit to receive an external signalon the liquid crystal display panel and to control the liquid crystaldisplay panel to display an image corresponding to the external signal,and a power supply unit to convert and distribute external power to thedrive unit and the signal processing unit.
 5. The outdoor displayapparatus according to claim 1, further comprising: an outlet filtercoupleable to an inside of the outlet port to remove dust from airdischarged through the outlet port.
 6. The outdoor display apparatus ofclaim 1, wherein the temperature controlling unit includes a fan to drawair through the inlet port.
 7. The outdoor display apparatus of claim 6,wherein the temperature controlling unit further includes a heater toraise the temperature inside the housing, the heater being disposedbetween the filter and the fan.
 8. The outdoor display apparatus ofclaim 6, further comprising an air circulation device to distribute airintroduced through the inlet port.
 9. The outdoor display apparatus ofclaim 8, the air circulation device comprising: a dividing structure,wherein the dividing structure is configured such that a first portionof the air passes through the gap between the transparent member and theliquid crystal display panel and a second portion of the airsimultaneously passes through the circuit, the first portion and thesecond portion of the air being discharged through the outlet port. 10.The outdoor display apparatus of claim 9, wherein the air circulationdevice further comprises a guide duct, in which a fan is disposed. 11.The outdoor display apparatus of claim 10, wherein the guide ductincludes a first discharge port to guide the first portion of airdischarged from the fan to the gap between the transparent member andthe liquid crystal display panel, and a second discharge port to guidethe second portion of the air discharged from the fan to the circuit.12. The outdoor display apparatus according to claim 8, wherein the aircirculation device is disposed at a lower part of the housing, the inletport is provided at the lower part of the housing, and the outlet portis provided at an upper part of the housing.
 13. The outdoor displayapparatus according to claim 8, wherein the air circulation devicecomprises: a guide duct, in which the fan is disposed, having a firstdischarge port to guide the first portion of air discharged from the fanto the gap between the transparent member and the liquid crystal displaypanel.
 14. The outdoor display apparatus according to claim 13, whereinthe guide duct comprises a second discharge port to guide the secondportion of the air discharged from the fan to the circuit.
 15. Theoutdoor display apparatus according to claim 14, wherein the firstportion of the air guided by the first discharge port is about 70% ofthe air discharged from the fan, and the second portion of the airguided by the second discharge port is about 30% of the air dischargedfrom the fan.
 16. An outdoor display apparatus comprising: a housinghaving an opening formed at a front portion of the housing; atransparent member disposed in the opening of the housing; a displaypanel module disposed in the housing, having a display panel spacedapart from the transparent member to define a first gap and to displayan image thereon and having a circuit disposed in a rear portion of thehousing to define a second gap; an inlet port to introduce air into thehousing; an outlet port to discharge the air passing through the firstgap and the second gap of the housing; a filter coupleable to an insideof the inlet port to remove dust from air introduced through the inletport; a temperature controlling unit configured to control a temperatureof an inside of the housing and disposed between the filter and thefirst gap and the second gap, and an optical film disposed on a viewingpath of the image, wherein the optical film extends parallel to thedisplay panel to an outside of the housing to control light passingbetween the transparent member and the display panel, the optical filmincluding: a polarizing film having an optical axis the same as anoptical axis of light passing through the display panel, and a ¼wavelength plate to convert an optical axis of the image displayed onthe display panel into circular polarized light having an optical axisperpendicular to the optical axis of the polarizing film that is thesame as the optical axis of the liquid crystal display panel, andwherein the liquid crystal display panel is configured to reflect thecircular polarized light that has passed through the ¼ wavelength plate,and the ¼ wavelength plate is a single ¼ wavelength plate of the outdoordisplay apparatus which converts the optical axis of the image in theoutdoor display apparatus.
 17. The outdoor display apparatus of claim16, wherein the optical film reduces at least one of transmission oflight transmitted through the transparent member and the light beingreflected off of the display panel.
 18. The outdoor display apparatus ofclaim 16, wherein the temperature controlling unit includes a fan todraw air through the inlet port and a drive motor to rotate the fan. 19.The outdoor display apparatus of claim 18, wherein the temperaturecontrolling unit further includes a heater to heat the air, the heaterbeing selectively activated to raise a temperature inside of the housingbased on a sensor that is disposed on and/or inside the housing, whereinthe circuit of the display panel module is a first heat generatingsource to be cooled by non-temperature-controlled air of the aircirculation device.
 20. The outdoor display apparatus of claim 18,further comprising an air circulation device to distribute a selectivelytemperature-controlled air into the first gap and the second gap. 21.The outdoor display apparatus of claim 20, the air circulation devicecomprising: a dividing structure disposed between the fan and thedisplay panel module to divide the air so that a first portion of theair passes into the first gap and a second portion of air simultaneouslypasses through the second gap.
 22. The outdoor display apparatus ofclaim 21, wherein the air circulation device further comprises a guideduct, in which the fan is disposed.
 23. The outdoor display apparatus ofclaim 22, wherein the guide duct includes a first discharge port toguide the first portion of air discharged from the fan to the first gapbetween the transparent member and the display panel, and a seconddischarge port to guide the second portion of the air discharged fromthe fan to the circuit.